Duncan Jones doesn't have an excellent portfolio. His most recent works, Warcraft and Mute, have been viewed quite negatively by critics, although those two films seem to have niche audiences, Jones' best works are his earliest. Although, even though his more recent works aren't amazing, one can admire the creativity behind them.
Source Code, released in 2011, however, is excellent. Starring Jake Gyllenhaal as helicopter pilot Colter Stevens, Source Code is a near-future thriller set in a moderately dystopian world. His mission top-secret, and has him entering a virtual world as Sean Fentress, to live out his final minutes on a train, shortly before it is bombed. Stevens is tasked with discovering the identity of the bomber during those few minutes in order to prevent a similar event.
This film is excellently made, and mostly due to its simplistic nature. Its narrative unfolds over its runtime, but focuses on the simplicity of location and strong dialogue and character development. Duncan Jones manages to pull off simplicity and character development very, very well -- if you've seen Moon, you'll know what I mean -- and it allows for a very unexpected course of events, and ultimately an unforgettable ending.
Stevens wakes up on the train, he's disorientated and unsure of his identity. The bomb goes off, killing everyone. Stevens wakes up in a cockpit, communicating with an Air Force Captain, she verifies his identity as Stevens. The viewer learns of this at the same time as the character, and that's how a large portion of the film unfolds. there's mystery behind everything, a greater conspiracy is at work, but Stevens is advised to stay on mission.
The ways in which Source Code displays the virtual world is unique; it's nothing overly revolutionary, but it functions and ensures Stevens is capable of creating an environment (the cockpit) despite being on life support and unable to communicate with the outside world without it.
Source Code battles the concept of space and time, dealing with this alternate timeline to reverse actions that have occurred in the original timeline; this allows Stevens to survive having stopped and reversed the bombing in both timelines, despite dying in the original. It's a twist that's mostly unexpected, and holds a ton of emotional weight as a result of Stevens' actions and character development within the alternate timeline.